Used to be an engineer for the most popular fashion/womens blog in the world. This method works for 2 reasons.
1) Pinterest has a huge but very focused base of users. That means it gets huge traffic, but only for a few topics. Fashion, crafty stuff, recipes and some other things women like. This limits your options, so the amount of people trying to game it is much lower than Twitter, Facebook, etc. At the same time, this means they're looser with the rules because they don't have a flood of spam to combat.
2) Fashion is an extremely profitable niche. Women are pretty much always ready to shop online. All you really have to do is show them something they want and they'll buy it. You also get to offer lots of different things so having a stream of return visitors is great. With lots of other markets, you're trying to sell one product to a user and they're useless after that. With fashion you can keep showing new products to the same people and they'll buy more.
Tips:
1) The biggest thing you should consider is the quality of your products. Quality matters much more than quantity here. For example, one post of a really hot new handbag will bring in more sales than 100 random average ones.
2) There's viral potential here. If you find that hot product and host the image, it will get pinned by people. Also, the same products that sell are the ones that get a lot of pins. If you pick your products right, how many people you blast it out to initially won't matter all that much. Even if you have an initial reach of 100, your best content can get 10,000 or 100,000 hits at the end of the day. If you post something mediocre, you're only going to reach that 100 people and they won't buy it anyway.
2B) Be sure to use social buttons and whatnot. Make images pinnable, etc. It's easy to do and goes a long way.
3) Sourcing products and content is scientific. Even if you don't know about fashion, you can collect the right data from other sources with their social metrics. Go look at a big fashion blog and you'll see that some posts get 10 likes and some get 10,000. If you see a post that's way above average and it pertains to a product, that's going to be a winner. If it's available on Amazon you've got a post.
If you really want to scale, this is where you do it. Even at the big sites like I was at, research is king. Everything is driven by social metrics. It's all automated. The best thing you can do is catch something that hasn't blown up yet but is showing promise on a small scale and be the one to actually blow it up.
4) Coming off as an influencer goes a long way. A big part of why fashion is so profitable is that you have the ability to put the idea in a woman's head that this product is something she wants. You basically want to be a blog not a store. Write (or steal) a short post about why this thing is awesome. Make it really short, this is a subtle sales technique not copy for SEO. Not as short as a tweet, but maybe as short as 3 tweets.
5) To expand on 4, the feel of your site should be a blog written by a person with good taste. This is why it's fine to use blogspot or something like that. Don't use a theme that's too "professional". It can be very very basic (think tumblr). The main thing you want to worry about is limiting your content to that really good stuff. The worst thing that can happen is you have someone land on a blog where all the other posts are for ugly stuff. If you do that, she might actually assume you have bad taste and not want to buy anything you support.
That's the basics. Have fun.